ON FINDING LOWEST COMMON ANCESTORS - SIMPLIFICATION AND PARALLELIZATION

被引:311
作者
SCHIEBER, B
VISHKIN, U
机构
[1] TEL AVIV UNIV,SCH MATH SCI,DEPT COMP SCI,IL-69978 TEL AVIV,ISRAEL
[2] NYU,COURANT INST MATH SCI,DEPT COMP SCI,NEW YORK,NY 10012
关键词
Computer Systems; Digital--Parallel Processing - Mathematical Techniques--Trees;
D O I
10.1137/0217079
中图分类号
TP301 [理论、方法];
学科分类号
081202 ;
摘要
We consider the following problem. Suppose a rooted tree T is available for preprocessing. Answer on-line queries requesting the lowest common ancestor for any pair of vertices in T. We present a linear time and space preprocessing algorithm that enables us to answer each query in O(1) time. Our algorithm has the advantage of being simple and easily parallelizable. The resulting parallel preprocessing algorithm runs in logarithmic time using an optimal number of processors on an EREW PRAM. Each query is then answered in O(1) time using a single processor.
引用
收藏
页码:1253 / 1262
页数:10
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